Greenhouse

ABSTRACT

A closure assembly for a greenhouse has a first piece connectable to the roof, and a second piece connectable to the wall. The first piece is connectable to the second piece to form a pivotable joint therebetween for forming a joint between the roof and the wall. A shading system extends between purlins mounted over roof rafters, and vent screens and vent operators are mounted below glazing bars extending over the purlins.

This application claims the benefit of U.S. Provisional ApplicationSerial No. 60/671,584, filed Apr. 15, 2005, the entirety of which isincorporated by reference herein.

FIELD OF THE INVENTION

The present invention relates generally to greenhouses and, moreparticularly, to an improved greenhouse.

BACKGROUND OF THE INVENTION

A greenhouse is a structure that traps solar radiation and is used topropagate, cultivate and/or exhibit plants. A greenhouse has a glazingsystem that is an assembly of one or more lites that provide a weatherbarrier. A lite is an area or panel of a glazing system that allowssunlight to pass therethrough, and a lite is often glass but may be madeof other materials. A greenhouse often provides for the regulation oflight, temperature and/or humidity.

Greenhouse construction has changed little since metal framedgreenhouses first appeared around 1855, and a relatively standardgreenhouse design and construction was well established by 1900. Forexample, glazing bar centers were separated by 24.75 inches, and roofswere designed with a 6/12 pitch for ease of construction andengineering. Lites were formed from a glass glazing material that wasalmost exclusively 0.125 inch B grade glass pane measuring 24×26 inches.The glass panes were supported at their lateral edges by glazing barsand were shingled from eave to ridge of the roof with unsealed jointsoverlapping by about 0.375 inch at their upper and lower edges. Theglazing panes were sealed to the glazing bars with a glazing compound,for example, a putty or other sealant. At that time, the development ofgreenhouse designs was generally limited by glass manufacturingtechnology.

More recent greenhouses are made with steel or aluminum frames andaluminum glazing bars; and better sealants, such as, butyl “rope putty”,are used. Other glazing materials, for example, plastic non-glassglazing materials, have been developed and used in greenhouses, and suchglazing materials often allow a larger rafter spacing. Non-glass panelshave been used with varying degrees of success. The thermal expansionproperties of plastic nonglass glazing materials demanded that anothersealing method be developed. Elastomeric glazing gaskets are currentlyused in place of glazing compounds to cushion and seal the non-glassglazing panels to the glazing bars, but such elastomeric glazing gasketsare not generally used in glass glazing systems.

Many non-glass glazing materials experience a degradation caused byexposure to ultraviolet light in sunlight. This degradation changes thequality of light transmitted through the glazing. In greenhouseapplications requiring a consistent, controllable and/or predictableexposure to sunlight, for example, in research greenhouses, glassglazing is still preferred. Thus, other than the improvements inmaterials, the design of greenhouses, including the dimensional andstructural details, remains relatively unchanged.

The requirements for research greenhouses differ from those used forcommercial plant production and present more demanding and stringentrequirements with respect to being able to create, and accuratelyrecreate, a wide variety of growing conditions, as well as providesunlight uniformly throughout the plant growth area. For example,although the design and construction of research greenhouses haven'tchanged much in the last century, there has been a substantial increasein the variety of systems available for use in the greenhouse.Supplemental lighting, requirements for photoperiod manipulation,fertilizer injection systems, evaporative cooling systems, high pressurefog systems, automatic shade systems, circulation fans, microprocessorbased environmental controls, and more have all been made available to aresearch greenhouse user. This equipment in addition to more typicalmechanical, electrical and plumbing requirements are often mounted inconvenient locations inside the greenhouse This large amount of supportequipment not only may use valuable space inside of the plant growtharea but also, may cast shadows that interfere with the availability ofsunlight. However, in a research greenhouse, the ability to conductrepeatable experiments and obtain high quality data requires thatchanges in exposure to sunlight caused by greenhouse components beminimized if not eliminated.

Meeting the more demanding and stringent requirements for researchgreenhouses is also more difficult given various known constructionpractices. For example, first, a majority of research greenhouses areframed with trusses separated by about 10 feet. The trusses sit on postsand are connected together by horizontally extending girts. A glazingsystem is then attached to the girts to enclose the building. Thetrusses present a substantial structure that is below the glazing systemand casts shadows over different areas of the plant growth area.

Second, research greenhouses are often constructed in the midst of aheavily congested university campus and may be built on existingbuilding roofs or as a wing of an existing or a new building. Theseconditions often dictate a roof slope other than the industry standard6/12 pitch. Trim joints between the side walls and the roof are oftenmade from a custom-designed aluminum extrusion. Further, a differentcustom-designed aluminum extrusion is required for each different roofpitch. In addition, another custom-designed aluminum extrusion is neededfor the joints between the roof and gabled end walls. Therefore, designsemploying nonstandard roof pitches add substantial costs to theconstruction.

Third, automated shade and/or heat retention systems have become almostuniversal in research greenhouses. Shades cut down solar gain in thedaytime, which greatly improves an ability to maintain a temperaturerange; and shades may also be used to retain heat in cold weather. Onecurrent practice is to hang the shades in a sloped-flat-slopedconfiguration between the trusses, and the shades are pulledhorizontally from truss to truss to close. The presence of the shadesbelow the trusses reduces the number of places where additionalcomponents and equipment can be mounted. Further, in most installations,such a shade mounting may result in gaps along the shade edges andbetween the shades. Such gaps are often closed using separate closingshades. In addition, gaps may occur in odd size bays, where a partitionis located at an end of the greenhouse and/or at an area where the shadecannot be fully retracted.

Fourth, with many research greenhouses, screens are located above therafters in vent openings on the roof. In this location, it is necessaryfor vent operator arms to pass through respective screens, therebycompromising their function as an insect barrier. Also, replacing ascreen requires dismantling the vent operator, which is labor intensiveand expensive.

Fifth, known inside gutter systems are used to direct condensate andwater infiltration to interior collectors and drain lines. The drainlines extend downward from the gutter system to direct the water tointerior floor drains or drain lines that extend through a greenhousewall near floor level. The interior collectors and drain lines providefurther structure in the plant growth area that adds cost and caninterfere with other components as well as user access.

Sixth, known roof vent operators are located below rafters and moverespective long, curved rack arms back and forth to open and closerespective vents. When the vents are closed the long rack arms extendwell into the greenhouse interior and may interfere with othergreenhouse components as well as cast unwanted shadows inside thegreenhouse plant growth area.

Advancements in equipment design and microprocessor based environmentalcontrols have added many opportunities for shadows from the equipmentand the supply and control plumbing and conduit. In addition, currentplant growth research often involves transgenic and genetically modifiedorganisms (GMO's) and thus, requires higher levels of containment thanare available using current greenhouse standards.

Therefore, there is a need for a greenhouse that addresses the aboveproblems.

SUMMARY OF THE INVENTION

The present invention provides a greenhouse that meets the moredemanding and stringent requirements for a research greenhouse, has aclean uncluttered interior architecture and permits the use of steel,polymer and aluminum structural shapes as applications dictate withoutchanging the basic greenhouse design. The greenhouse of the presentinvention has an exterior trim closure that permits common parts to beused along side walls for roofs of different pitches as well as alonggabled end walls. Thus, the exterior trim closure eliminates the costsof designing and handling different extrusions for different roofpitches. Further, the exterior trim closure reduces labor and timerequired to assemble closures around the roof and therefore, is lessexpensive to construct.

In accordance with the principles of the present invention and thedescribed embodiments, the invention in one embodiment provides agreenhouse with a roof and a wall. A closure assembly has a first piececonnectable to the roof, and the first piece has a first jointcomponent. The closure has a second piece connectable to the wall, andthe second piece has a second joint component. The second jointcomponent is connectable to the first joint component to form apivotable joint therebetween, and the pivotable joint forms a jointbetween the roof and the wall. The pivotable joint allows a commonclosure assembly to be used to connect walls to roofs of any pitch aswell as mutually perpendicular walls to each other.

In another embodiment of the invention, the greenhouse has two rafterswith at least two purlins extending over, and connected to, the rafters.A roof glazing system has at least one roof lite and extends over, andis connected to, the at least two purlins. A flexible material, forexample, a shading or heat retention material, is located above therafters and between the at least two purlins and is movable to block andunblock light from the at least one roof lite of the roof glazingsystem. With the flexible material located above the rafters, a moreuniform shaded area is provided; and more locations are available on therafters for mounting accessories and other equipment.

In a further embodiment of the invention, the roof glazing system of thegreenhouse has two glazing bars and a vent movable with respect to thetwo glazing bars to open and close a vent opening. A vent operatorhaving an extendable drive is operably connected to the vent and mountedabove the rafters. The vent operator is operable to open and close thevent while maintaining an entirety of the extendable drive above therafters. In one aspect of this invention, the vent operator is ascissors extension arm. Therefore, the vent operator does not intrudeinto the greenhouse interior.

In a still further embodiment of the invention, a screen is mountedbelow the glazing bars and the vent operator; and thus, the screen doesnot require any opening to accommodate the vent operator.

In yet another embodiment of the invention, an interior gutter extendsalong an upper portion of the a wall glazing system below the roofglazing system. The interior gutter system has a weep hole for directingwater and condensate from the interior gutter system to an exterior ofthe greenhouse. Thus, the interior gutter system eliminates interiorcollectors and drains carrying water below the interior gutter system.

Various additional advantages, objects and features of the inventionwill become more readily apparent to those of ordinary skill in the artupon consideration of the following detailed description of embodimentstaken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated herein and constitutea part of this specification, illustrate embodiments of the inventionand, together with a general description of the invention given above,and the detailed description of the embodiments given below, serve toexplain the principles of the invention.

FIG. 1 is a cut-away perspective view of a greenhouse in accordance withthe principles of the present invention.

FIG. 2 is a cross-sectional view illustrating an intersection between aroof glazing system and a side wall glazing system.

FIG. 3 is an enlargement of a portion of the cross-sectional view ofFIG. 2 further illustrating a closure trim piece.

FIG. 4 is an enlargement of a portion of the cross-sectional view ofFIG. 3 further illustrating a snap connector of a closure trim piece.

FIG. 5 is a cross-sectional view illustrating an intersection between aroof glazing system and a gable portion of an end wall glazing system.

FIG. 6 is a cross-sectional view illustrating an intersection between anend wall glazing system and an side wall glazing system.

FIG. 7 is an enlarged view of a portion of FIG. 1 illustrating a shadein an area under a single roof lite.

FIG. 8 is a cross-sectional view of a roof glazing system illustrating avent, vent operator and vent opening screen.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, an exemplary greenhouse 20 is constructed from aframe structure 21 supporting glazing systems 24, 25 and 28. A lowerframe 22 supports an end wall glazing system 24 forming a first end walland a side wall glazing system 25 forming a first side wall. An upperframe 26 supports a roof glazing system 28. The end wall and side wallglazing systems 24, 25 can also be used to formed an opposed second endwall and an opposed second side wall, which are not shown in FIG. 1. Thelower frame 22 is comprised of a plurality of substantially verticalposts 30 that are generally equally spaced, for example, every fourfeet, around a perimeter of the greenhouse 20. The vertical posts 30 aresecured at their lower ends to a concrete footer in a known manner asshown in FIG. 2. As shown in FIGS. 1 and 2, the upper frame 26 hasrafters 32 that are connected at outer or lower ends 34 to upper ends ofthe vertical posts 30. Inner or upper ends of opposing rafters 32 areconnected to each other along a roof ridge 36 as shown in FIG. 8. Aplurality of purlins 38 (FIGS. 1 and 2) are attached to upper surfacesof the rafters 32 and extend in a direction substantially perpendicularto the rafters 32. The purlins 38 are used to support the roof glazingsystem 28. The roof glazing system 28 typically includes verticalglazing bars 40 attached to the purlins 38. Horizontal glazing bars 42extend between, and are supported by, the vertical glazing bars 40. Roofglass lites 44 are mounted within the vertical and horizontal glazingbars 40, 42. The roof glass lites 44 are fabricated from a laminatedglass and typically measure 4×5 ft. The end wall glazing system 24 useshorizontal glazing bars 46 that support vertical glazing bars 48 as wellas wall glass lites 50. Substantially similar wall lites 50 are used inboth the end wall glazing system 24 and the side wall glazing system 25.

One challenge in constructing the greenhouse 20 is providing astructural interface or connection between the glazing systems 24, 25and the roof glazing system 28. More particularly, exterior trim must beprovided along an eave, that is, an intersection line 52 between theside wall glazing system 25 and the roof glazing system 28. In addition,exterior trim must be provided along an intersection line 54 between theroof glazing system 28 and a gable portion 56 of the end wall glazingsystem 24. As previously discussed, it is known to use custom-designedaluminum extrusions for such trim but a different extrusion must be madefor each different roof pitch. Referring to FIGS. 2 and 3, a universalexterior closure or trim assembly 60 has a first roof trim piece 62 anda second side wall trim piece 64. The roof trim piece 62 has a firstsocket-type joint component 66 formed on a lower end 68. The side walltrim piece 64 has a pin-type second joint component 70 formed on anupper end 72. Thus, upon inserting the second joint component 70 into anopening 74 of the first joint component 66, the roof trim piece 62 andside wall trim piece 64 are able to be rotated or pivoted with respectto each other.

After the lower and upper frames 22, 26 and glazing systems 24, 25, 28are constructed as shown in FIG. 3, the wall trim piece 64 has anextruded slot 76 that is sized to receive an extruded projection 78extending upward from an uppermost horizontal glazing bar 46. A seal 80is mounted in the projection 78 and provides a seal with the wall trimpiece 64. A bracket 82 is used to secure the wall trim piece 64 to oneor more vertical glazing bars 40 of the roof glazing system 28. Afterthe wall trim piece 64 is mounted, the opening 74 of the socket jointcomponent 66 on the roof trim piece 62 is aligned with, and pushed over,the end 84 of the pin joint component 70. Upon the pin joint component70 being inserted in the socket joint component 66, the roof trim piece62 is rotatable or pivotal with respect to the pin joint component 70and the side trim piece 64. Thus, as shown in phantom in FIG. 4, theroof trim piece 62 can be moved to any desired angle with respect to thewall trim piece 64 to accommodate any pitch of the roof glazing system28. The roof trim piece 62 is pivoted toward the horizontal glazing bar42.

Referring to FIG. 4, a pair of first ribs 86 are extruded on a lowersurface 88 of the roof trim piece 62. A pair of opposing ribs 90 areextruded on an upper surface 92 of the horizontal glazing bar 42. Theribs 86, 90 are shaped and located relative to each other such that uponthe roof trim piece 62 being pushed against the horizontal glazing bar42, the ribs 86 snap over the ribs 90 to secure the roof trim piece 62with the horizontal glazing bar 42. A spacing leg 94 extruded on theroof trim piece bottom surface 88 is designed to rest against an uppersurface 96 of a vertical glazing bar 40 to provide further strength andstability to the roof trim piece 62. Thus, referring to FIG. 1, the roofand wall trim pieces 62, 64 are used to define an exterior joint orcorner at an eave 52 between the roof glazing system 28 and the sidewall glazing system 25 of the greenhouse 20.

As shown in FIGS. 1 and 5, a substantially similar exterior closure ortrim piece 98 can be used to form external corners creating a joint atthe intersection line 54 between the roof glazing system 28 and a gableportion 56 of the end wall glazing system 24. The closure 98 iscomprised of the roof trim piece 62 that connects to a vertical glazingbar 40 defining a lateral edge of the roof glazing system 28 and asecond wall trim piece 104 that connects to an upper-most horizontalglazing bar 46 in a gable portion 56 of the end wall glazing system 24.The roof trim piece is substantially identical to the roof trim piece 62shown and described in FIGS. 3-5. The vertical glazing bar 40 has a pairof ribs 100 extruded on an outer directed surface 102. Upon the rooftrim piece 62 being located over, and pushed against, the verticalglazing bar 40, the ribs 86 snap over and connect with the ribs 100.

The second wall trim piece 104 has a pin-type joint component 70identical to that shown and described in FIG. 3 with respect to the trimpiece 64. In addition, the second wall trim piece 104 has a pair of ribs106 extruded along an inner surface 107, and the horizontal glazing bar46 has a pair of ribs 108 extruded along an outer surface 110. Upon thewall trim piece 104 being located over, and pushed against, thehorizontal glazing bar 46, the ribs 106 snap over and connect with theribs 108.

Referring to FIG. 6, a substantially identical wall closure 98 is usedto form external corners creating intersections between the lateraledges of the end wall glazing system 24 and the side wall glazing system25. In this embodiment, the trim piece 62 is located adjacent a lateralvertical glazing bar 48 a of the side wall glazing system 25. Thevertical glazing bar 48 a has a pair of ribs 112 extruded along an outersurface 114; and upon the trim piece 62 being located over, and pushedagainst, the vertical glazing bar 48 a, the ribs 86 snap over andconnect with the ribs 112. Similarly, the trim piece 104 is locatedadjacent a lateral vertical glazing bar 48 b of the end wall glazingsystem 24. The vertical glazing bar 48 b has a pair of ribs 116 extrudedalong an outer surface 118; and upon the trim piece 104 being locatedover, and pushed against, the vertical glazing bar 48 b, the ribs 106snap over and connect with the ribs 116. Thus, all intersections betweenthe end wall glazing system 24, side wall glazing system 25 and roofglazing system 28 of any pitch are provided by the same three extrudedtrim pieces 62, 64, 104. Further, the external joint provide by the trimassembly 60 is highly resistant to water infiltration; and if properlysealed is effective to contain air and allows the plant growth area tobe maintained at a pressure slightly less than atmospheric pressure.

Referring to FIGS. 1 and 7, the greenhouse 20 has an exemplary shadesystem comprised of individual shades 120 a-120 f for each of the rooflites 44. In one example shown in FIG. 7, a shade 120 a is illustratedin an open position and is located adjacent an upper facing side of apurlin 38 a. To close the shade 120 a, a lead bar 132 is pulled upwardtoward the roof ridge 36, and the shade 120 a is moved in a directionparallel to the roof lite 44. When fully closed, the lead bar 132 islocated adjacent a lower facing side of a purlin 38 b; and lateral edges134, 136 of shade 120 a lie on upper surfaces of respective adjacentrafters 32 a, 32 b. Thus, the shade 120 a fully covers an area boundedby purlins 38 a, 38 b and rafters 32 a, 32 b below a roof lite 44 andeffectively blocks light without auxiliary or closing shades.

The shade 120 a is moved by a motor 122 mounted to the rafter 32 b belowthe purlin 38 b as further shown in FIG. 8. Referring back to FIG. 7, adrive shaft 124 is mechanically coupled to the motor 122 and has adistal end mounted on the rafter 32 a. Idler pulleys 126 a, 126 b aremounted on respective rafters 32 a, 32 b adjacent an upper facing sideof purlin 38 a. Drive cables 128, 130 extend between ends of the driveshaft 124 and respective idler shafts 126 a, 126 b. The drive cables128, 130 are also connected to ends of the leader bar 132 of the shade120 a. Thus, by operating the motor 122, the drive shaft 124 moves thedrive cables 128, 130 and pull the leader bar 132 from its open positionadjacent purlin 38 a to a closed position adjacent purlin 38 b. Byreversing operation of the motor 122, the drive cables 128, 130 move thelead bar 132 of the shade 120 a back to its open position adjacent theupper directed side of the purlin 38 a. With the above embodiment ofhaving a separately operable shade, a wide variety of lightingconditions can be created and accurately repeated.

As will be appreciated, many other embodiments of a shade system can beimplemented depending on needs of a particular user; and in otherembodiments, combinations of shades can be simultaneously operated. Forexample, mounting the motor 122 to a rafter 32 is only oneimplementation; and in other embodiments, the motor 122 can be mountedat other locations, for example, on a purlin 38 above the drive shaft124, in line with the drive shaft 124, etc. Further, motors forrespective shades 120 a-120 f (FIG. 1) can be operated independently butsimultaneously to partially or wholly open and then close all of theshades. In another exemplary embodiment, the shades 120 a, 120 b, 120 ccan be replaced by a single shade that extends over several lites 44,and a single drive shaft is operated by a motor to close and/or open thesingle shade extending between purlins 38 a, 38 b. Similarly, the shades120 d, 120 e, 120 f can be replaced by a single shade that extends overseveral lites 44, and a single drive shaft is operated by a motor toclose and/or open the single shade extending between purlins 38 b, 38 c.In a further embodiment, drive shafts of respective shades 120 a, 120 d,etc. can be mechanically coupled together and operated by a single motorto simultaneously close a vertical row of shades 120 a, 120 d, etc.extending between rafters 32 a, 32 b. In any of the above embodiments,the motors 122 can be eliminated; and the drive shafts 124 andrespective shades 120 can be operated manually, for example, by chains,cables, crank shafts, etc., that are located for ready operation by auser.

A decision of which shades to operate simultaneously is user andapplication dependent and thus, will vary with different greenhouses.However, regardless of how the shades are operated, locating the shades120 between the purlins 38 and above the rafters 32, has numerousadvantages. First, by extending only between the purlins 38, smallershades can be used; and a less bulky amount of shade material needs tobe collected when the shade is open. Further, when open, the shades aremostly hidden in the purlins above the rafters, which minimizes unwantedshading and shadows and further, enhances the openness of thegreenhouse. Second, the higher location of the shades above the rafters,frees up locations for the mounting of auxiliary equipment on therafters. Third, closing the shades over upper surfaces of the raftersresults in a good light seal between lateral edges of the shades and therafter upper surfaces and supplemental closing shades are not required.Fourth, the individual shades are smaller, which permits different typesof shades to be utilized again depending on a preference of the user.For example, shades that simply gather material in a closed position maybe utilized. Alternatively, shades that are rolled onto and off of acylinder can be used as well as shades that have an internal torsionalreturn spring that facilitates rolling the shade onto the cylinder asthe shade is opened. Therefore, such a shading system provides for moreaccurate, consistent, uniform and repeatable lighting conditions.

Referring to FIG. 1, movable wall vents 139 are used to provideventilation in the end and side wall glazing systems 24, 25. The movablewall vent 139 has an upper edge pivotally hinged adjacent horizontalglazing bars 46, so that a lower edge can pivot open as shown. Anoperator 146 a has a drive shaft 147 a supporting one or more operatordrives 148 a. Each operator drive 148 a has a pair of nuts 149 threadedon the drive shaft 147 a and connected to an inner end of a scissorsextension arm 153. An outer end of the scissors extension arm 153 isconnected to a lower edge of the wall vent 139. An operator motor (notshown) is connected to one end of the drive shaft 147 a. Operating themotor in one direction causes the nuts 149 to move toward each other,thereby extending the scissors extension arm 153 and pivoting the vent139 outward to an open position as shown in FIG. 1. Operating the motorin an opposite direction causes the nuts 139 to move away from eachother, thereby retracting the scissors extension arm 153 and pivotingthe vent 139 inward to a closed position. In different embodiments, thedrive shaft 147 a may extend through holes in webs of respectivevertical posts 30 or, alternatively, may be mounted to inner directedsurfaces of respective vertical posts 30. Thus, whether the vent 139 isopen or closed, the operator 146 a remains substantially between thevertical posts 30 and does not extend into the plant growth area. Thus,the compact construction of the operators 146 a substantially reduces apotential for physical interference with persons working in thegreenhouse, allows more space for unimpeded activity and thus, caneffectively increase available plant growth area.

Referring to FIG. 8, vents 138 are used to provide ventilation throughthe roof glazing system 28. An upper end 140 of a vent 138 includes apin-type component 141 of a hinge 142 that has a socket-type component143 located near the roof ridge 36. Thus, the vent 138 is pivotablebetween a closed position shown in solid lines and an open positionshown in phantom. A lower end 144 of the vent 138 is connected to anoperator 146. The operator 146 has a drive shaft 147 extending betweenand mounted to lower surfaces 151 of adjacent vertical glazing bars 42.An operator drive 148, for example, a compact scissors extension arm,which has an upper end connected to a movable edge of the vent 138 and alower end connected to nuts threadedly engaged on the drive shaft 147. Adrive motor 150 is operably connected to the drive shaft 147. In theembodiment of FIG. 8, the drive motor 150 is secured to a glazing bar42; but in alternative embodiments, the drive motor 150 may be mountedto a purlin 38 with a belt or pulley drive connecting the motor to thedrive shaft 147. Operating the motor 150 in one direction causes thenuts to move toward each other, which extends the scissors extension armas shown in phantom at 148. The extending scissors extension arm pivotsthe vent 138 upward as viewed in FIG. 8 to an open position as shown inphantom. Operating the motor 150 in an opposite direction causes thenuts to move away from each other, thereby retracting the scissorsextension arm and pivoting the vent 138 downward to a closed position.The entirety of the operator 146 including the operator drive 148 andmotor 150 are located above the rafters 32. Thus, the compactconstruction and location of the operators 146 minimizes any intrusionof the operators into the greenhouse, which substantially eliminates anyshadows inside the greenhouse from the operator drive 148. Oneembodiment of the operators 146, 146 a is commercially available fromLock Antriebstechnik, Gmbh located in Ertingen, Germany.

When the vent 138 is open, an opening into an interior of the greenhouse20 is covered by screens 154 a, 154 b that are mounted adjacent to lowersurfaces 151 of respective vertical glazing bars 42. The screens 154 a,154 b provide a barrier preventing insects from entering a plant growtharea below the vertical glazing bars 42. The opening above the screens154 a, 154 b is bounded laterally by two adjacent vertical glazing bars42. An upper end of the opening is bounded by a ridge purlin 152. Aspace extending above the ridge purlin 152 between the two adjacentvertical glazing bars 42 is common openings covered by screens 154 a,154 b. A lower side of the opening is bounded by a spacer 156 mountedadjacent a lower surface of a horizontal glazing bar 40 and extendingbetween the two adjacent vertical glazing bars laterally bounding theopening. The spacer 156 has a lower surface 158 that is flush with thelower surface 151 of the two adjacent vertical glazing bars 42. Anoperator cover 160 extends between the two adjacent vertical glazingbars 42 and has a lower edge 162 adjacent lower surfaces 151, 158. Thescreen 154 a has an upper edge 164 that fits beneath a purlin flange 166and a lower edge 168 that is held in place by a flange 170 on the cover160. A screen lateral edge 172 is located immediately adjacent thevertical glazing bar lower surface 151 and in some applications, may besecured thereto by fasteners and/or clips (not shown). Thus, the screens154 a, 154 b fully cover the opening beneath the vent 138. Further, withthe vent operator 146 above the screens 154 a, 154 b, the screens 154 a,154 b do not have any openings larger than a size of a screen mesh.Thus, the screens 154 a, 154 b provide an excellent barrier to the entryof insects either into or out of the greenhouse via the vent 138.

Referring back to FIG. 3, the wall trim piece 64 has an interior gutter174 extruded therein. Further, the gutter 174 has a weep hole 176 influid communication with a channel 178 leading to the exterior of thegreenhouse 20. Consequently, any condensation from the roof lites 44 orany infiltration of water is collected in the gutter 174.

The gutter 174 extends the full width across and above the side wallglazing system 25; and therefore, the gutter 174 is effective to captureall water that condenses from, or infiltrates through, the roof glazingsystem 28. Further, the water is drained via the weep hole 176 andchannel 178 to the exterior of the greenhouse, thereby eliminating theneed for any interior drainage system below the purlins 38.

The greenhouse 20 shown and described herein is designed with theequipment and performance requirements of today in mind. The greenhouse20 is an integrated system with very high weathering performance as abaseline. It also has flexibility designed in, which allows the bestconfiguration for a given site and use to be developed.

While the present invention has been illustrated by a description of anembodiment, and while such embodiment has been described in considerabledetail, there is no intention to restrict, or in any way limit, thescope of the appended claims to such detail. Additional advantages andmodifications will readily appear to those skilled in the art. Forexample, in the described embodiment, a research greenhouse isidentified as an application to which the inventions herein areparticularly well suited; however, it should be understood that theinventions described and claimed herein may be applied to any type ofgreenhouse. Further, in the exemplary embodiment described herein,glazing systems are used in the roof, the end walls and the sides walls;however, in other embodiments, glazing system(s) may be used in the roofand fewer than all of the walls, or in only the roof, or in only one ormore of the walls.

In addition, in the described embodiment, the trim assembly 60 is shownand described as creating a corner between two glazing systems. However,in alternative embodiments, a substantially similar trim assembly may beused to form a corner between a roof glazing system and a wall having noglazing system, or between a wall glazing system and a wall without aglazing system, or between two walls without a glazing system. Further,the trim joint 60 is shown and described as forming a corner that is onan exterior of the greenhouse; however, in an alternative embodiment,the trim joint 60 may be covered by a further piece of trim providing adrip edge extending beyond an edge of the roof and then downward. In afurther alternative embodiment, a drip edge may be extruded in the rooftrim piece 62 to provide a further barrier to water infiltration in highwinds.

Further, in the described embodiment, shades 120 are mounted above therafters 32 and extend in a direction perpendicular to purlins 38. Thelateral edges of the shades lie over upper surfaces of the rafters 32.In an alternative embodiment, the shades can be mounted at right anglesto the mounting shown and described. In this embodiment, the shadeswould extend over the rafters in a direction parallel to the purlins,and lateral edges of the shades would lie over an upper surface of lowerflanges of the purlins. Also, while a shade material 120 is described,in alternative embodiments, a heat retention material or any otherflexible material may be used.

Therefore, the invention in its broadest aspects is not limited to thespecific details shown and described. Consequently, departures may bemade from the details described herein without departing from the spiritand scope of the claims which follow.

1. A greenhouse comprising: a plurality of walls; and a closurecomprising a first piece connectable to a first wall and comprising afirst joint component, and a second piece connectable to a second walland comprising a second joint component, the second joint componentbeing connectable to the first joint component to form a pivotable jointtherebetween, the pivotable joint comprising a joint between the firstwall and the second wall.
 2. A greenhouse comprising: a wall; a roofsupported above the wall; and a closure comprising a first piececonnectable to the roof and comprising a first joint component, and asecond piece connectable to the wall and comprising a second jointcomponent, the second joint component being connectable to the firstjoint component to form a pivotable joint therebetween, the pivotablejoint comprising a joint between the roof and the wall.
 3. Thegreenhouse of claim 2 wherein the first joint component of the firstpiece comprises a socket-type component, and the second joint componentof the second piece comprises a pin-type component.
 4. The greenhouse ofclaim 2 wherein in the first piece comprises a first connector and theroof comprises a second connector connectable to the first connector forsecuring the first piece to the roof.
 5. The greenhouse of claim 2wherein the wall comprises a first connector and the second piececomprises a second connector connectable to the first connector forsecuring the second piece to the wall.
 6. The greenhouse of claim 2wherein the first piece and the second piece are extrusions.
 7. Thegreenhouse of claim 2 wherein the roof comprises a roof glazing systemand the first piece is connectable to the roof glazing system.
 8. Thegreenhouse of claim 2 wherein the wall comprises a wall glazing systemand the second piece is connectable to the wall glazing system.
 9. Thegreenhouse of claim 2 wherein the roof is nonperpendicular to the walland the first piece is connectable to the roof and the second piece isconnectable to the wall.
 10. The greenhouse of claim 2 wherein the roofis perpendicular to the wall and the first piece is connectable to theroof and the second piece is connectable to the wall.
 11. The greenhouseof claim 2 wherein the wall comprises an upper end and the second piececomprises an interior gutter extending below the roof adjacent an upperend of the wall, the interior gutter system comprising a weep hole fordirecting water and condensate from the interior gutter system to anexterior of the greenhouse.
 12. A greenhouse comprising: a first wallglazing system; a second wall glazing system; a closure comprising afirst piece connectable to the first wall glazing system and comprisinga first joint component, and a second piece connectable to the secondwall glazing system and comprising a second joint component, the secondjoint component being connectable to the first joint component to form apivotable joint therebetween, the pivotable joint comprising a jointbetween the first wall glazing system and the second wall glazingsystem.
 13. A greenhouse comprising: a roof glazing system; a wallglazing system; a closure comprising a first piece connectable to theroof glazing system and comprising a first joint component, and a secondpiece connectable to the wall glazing system and comprising a secondjoint component, the second joint component being connectable to thefirst joint component to form a pivotable joint therebetween, thepivotable joint comprising a joint between the roof glazing system andthe wall glazing system.
 14. An external trim piece for use with agreenhouse to form a joint between a wall and a roof of the greenhousecomprising: a first piece adapted to be connectable to the roof andcomprising a first joint component; and a second piece adapted to beconnectable to the wall and comprising a second joint component, thesecond joint component being connectable to the first joint componentand forming a pivotable joint therebetween, the pivotable joint forminga joint between the roof and the wall.
 15. A greenhouse comprising: aframe comprising at least two rafters; at least two purlins extendingover, and connected to, the at least two rafters; a roof glazing systemcomprising at least one roof lite, the roof glazing system extendingover, and connected to, the at least two purlins; and a flexiblematerial located above the at least two rafters and between the at leasttwo purlins and movable to block and unblock light from the at least onelite of the roof glazing system.
 16. The greenhouse of claim 15 whereinthe flexible material is a shade material.
 17. The greenhouse of claim15 wherein the flexible material is a heat retention material.
 18. Thegreenhouse of claim 15 further comprising a motor operably connected tothe flexible material, the motor being operable to move the flexiblematerial and block and unblock light from the at least one lite of theroof glazing system with the flexible material.
 19. The greenhouse ofclaim 15 wherein the flexible material comprises lateral edges extendingover upper surfaces of the rafters.
 20. The greenhouse of claim 15wherein the flexible material comprises lateral edges extending over,and resting against, upper surfaces of the rafters.
 21. A greenhousecomprising: a frame comprising at least two rafters; at least twopurlins extending over, and connected to, the at least two rafters; aroof glazing system extending over, and connected to, the at least twopurlins, the roof glazing system comprising two glazing bars, and a ventmovable with respect to the two glazing bars to open and close a ventopening; and a screen mounted below the glazing bars.
 22. The greenhouseof claim 21 wherein the two glazing bars have respective lower surfacesand the screen is mounted against the respective lower surfaces.
 23. Thegreenhouse of claim 22 further comprising a cover extending between thetwo glazing bars and the screen comprises: a first pair of opposed edgesmounted adjacent the two lower surfaces; a third edge mounted adjacentone of the purlins; and a fourth edge mounted adjacent the cover. 24.The greenhouse of claim 22 wherein the screen comprising: a periphery;and a screen mesh of a mesh size, the screen extending continuously andwithout an opening larger than the mesh size inside the periphery.
 25. Agreenhouse comprising: a frame comprising at least two rafters; at leasttwo purlins extending over, and connected to, the at least two rafters;a roof glazing system extending over, and connected to, the at least twopurlins, the roof glazing system comprising two glazing bars, and a ventmovable with respect to the glazing bars to open and close a ventopening; and a vent operator comprising an extendable drive operablyconnected to the vent and mounted above the rafters, the vent operatorbeing operable to open and close the vent while maintaining an entiretyof the extendable drive above the rafters.
 26. The greenhouse of claim25 wherein the extendable drive is a scissors extension arm.
 27. Thegreenhouse of claim 25 wherein the vent operator is mounted to the twoglazing bars.
 28. A greenhouse comprising: at least two substantiallyvertical posts; a wall glazing system extending over, and connected to,the at least two vertical posts, the wall glazing system comprising twoglazing bars, and a wall vent movable with respect to the glazing barsto open and close a wall vent opening; and a wall vent operator mountedto the at least two vertical posts and comprising an extendable driveoperably connected to the wall vent, the wall vent operator beingoperable to open and close the wall vent while maintaining an entiretyof the extendable drive substantially between the vertical posts. 29.The greenhouse of claim 27 wherein the extendable drive is a scissorsextension arm.
 30. A greenhouse comprising: walls; a roof glazing systemmounted above the walls; an interior gutter extending along an upperportion of the walls and below the roof glazing system, the interiorgutter system comprising a weep hole for directing water and condensatefrom the interior gutter system to an exterior of the greenhouse.
 31. Agreenhouse comprising: a frame comprising a lower frame, and an upperframe connected to the lower frame; a wall glazing system connected tothe lower frame; a roof glazing system connected to the upper frame; afirst piece connectable to the roof glazing system and having a firstjoint component; a second piece connectable to the wall glazing systemand having a second joint component pivotably connectable to the firstjoint component and connecting the wall glazing system with the roofglazing system; and an interior gutter extending above the wall glazingsystem and below the roof glazing system, the interior gutter systemcomprising a weep hole for directing water and condensate from theinterior gutter system to an exterior of the greenhouse.
 32. Thegreenhouse of claim 31 wherein the second piece is integral with theinterior gutter system.
 33. A greenhouse comprising: vertical posts; awall glazing system extending over, and connected to, the at least twovertical posts, rafters connected to the vertical posts; at least twopurlins extending over, and connected to, at least two rafters; a roofglazing system comprising at least one roof lite, the roof glazingsystem extending over, and connected to, the at least two purlins, afirst closure comprising a first piece connectable to the roof glazingsystem and comprising a first joint component, and a second piececonnectable to the wall glazing system and comprising a second jointcomponent, the second joint component being connectable to the firstjoint component to form a pivotable joint therebetween, the pivotablejoint comprising a joint between the roof glazing system and the wallglazing system.
 34. The greenhouse of claim 33 wherein the first jointcomponent of the first piece comprises a socket-type component, and thesecond joint component of the second piece comprises a pin-typecomponent.
 35. The greenhouse of claim 33 wherein the wall glazingsystem comprises an end wall glazing system and a side wall glazingsystem and the greenhouse further comprises: a second closure comprisinga first piece connectable to the end wall glazing system and comprisinga first joint component, and a second piece connectable to the side wallglazing system and comprising a second joint component, the second jointcomponent being connectable to the first joint component to form apivotable joint therebetween, the pivotable joint comprising a jointbetween the end wall glazing system and the side wall glazing system.36. The greenhouse of claim 33 further comprising a flexible materiallocated above the rafters and between the at least two purlins andmovable to block and unblock light from the at least one lite of theroof glazing system.
 37. The greenhouse of claim 36 wherein the flexiblematerial comprises lateral edges extending over, and resting against,upper surfaces of the rafters.
 38. The greenhouse of claim 33 whereinthe roof glazing system comprises two glazing bars and a roof ventmovable with respect to the glazing bars to open and close a roof ventopening, and the greenhouse further comprises a screen for the roof ventopening mounted below the glazing bars.
 39. The greenhouse of claim 38wherein the two glazing bars have respective lower surfaces and thescreen is mounted against the respective lower surfaces.
 40. Thegreenhouse of claim 38 further comprising a roof vent operatorcomprising an extendable drive operably connected to the roof vent andmounted above the rafters, the roof vent operator being operable to openand close the roof vent while maintaining the entirety of the extendabledrive above the rafters.
 41. The greenhouse of claim 40 wherein theextendable drive is a scissors extension arm.
 42. The greenhouse ofclaim 33 wherein the wall glazing system comprises two glazing bars anda wall vent movable with respect to the two glazing bars to open andclose a wall vent opening, and the greenhouse further comprises a ventoperator mounted to the at least two vertical posts and comprising anextendable drive operably connected to the wall vent, the vent operatorbeing operable to open and close the wall vent while maintaining anentirety of the extendable drive substantially between the verticalposts.
 43. The greenhouse of claim 42 wherein the extendable drive is ascissors extension arm.
 44. The greenhouse of claim 33 wherein the wallglazing system comprises an upper end and the second piece comprises aninterior gutter extending below the roof glazing system adjacent theupper end of the wall glazing system, the interior gutter systemcomprising a weep hole for directing water and condensate from theinterior gutter system to an exterior of the greenhouse.